[OSM-talk] [tagging] RFC :left/:right (asymmetrical roadside features)

Andy Allan gravitystorm at gmail.com
Tue Feb 17 10:36:16 GMT 2009


On Mon, Feb 16, 2009 at 7:11 PM, Norbert Hoffmann
<nhoffmann at spamfence.net> wrote:
> Andy Allan wrote:
>
>>And every time using :left and :right comes up, we all have a big
>>discussion about it and then nobody pays any attention and it comes up
>>again a few months later.
>
> Perhaps this is because the concept "left"<>"right" is so simple - and the
> aversion against editors, that are not totally key-ignorant is not so easy
> to understand.

And nobody pays attention. The main problem is that two-way roads have
no inherent, real-world, "direction" - neither side of the road is the
right or the left. Or rather, both sides of the road are the right or
the left, depending on which way you are facing. The only place that
right and left has any intrinsic sense is on one-way roads, which *do*
have an inherent direction (and signs to that effect).

Let's say you have a church beside a road. If it's a oneway street, it
makes some kind of sense to say "it's halfway along the road, over on
the left".

Let's say you have a church beside a two-way road. If I said "it's
halfway along the road, over on the right", you still wouldn't know
which side of the road it is on.

Now the problem is that most people at the moment in OpenStreetMap are
tech-heads, and are so used to mental constructs and abstractions like
every road having a completely arbitrary intrinsic direction - but
that doesn't mean it's a great idea. Editor support is less important
- and far easier to fix - than explaining to all the people who don't
even realise that all roads have a direction in openstreetmap - and
except for oneway roads, I have no idea which ways are pointing in
which directions, and it shouldn't be important unless it *has* to be
important.

Cheers,
Andy




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